二叉树的镜像

二叉树的镜像定义：源二叉树 
    	    8
    	   /  \
    	  6   10
    	 / \  / \
    	5  7 9 11
    	镜像二叉树
    	    8
    	   /  \
    	  10   6
    	 / \  / \
    	11 9 7  5

class TreeNode:
    def __init__(self, x):
        self.val = x
        self.left = None
        self.right = None
class Solution:
    # 返回镜像树的根节点
    def Mirror(self, root):
        if root == None:
            return None
        # 处理左子树
        temp = root.left
        root.left = root.right
        root.right = temp
        self.Mirror(root.left)
        self.Mirror(root.right)

class Solution:
    def Mirror(self, root):
        if root == None:
            return None
        stack = [root]
        while stack:
            node = stack.pop()
            if node.left:
                stack.append(node.left)
            if node.right:
                stack.append(node.right)
            node.right,node.left = node.left, node.right
        return root